Abstract: Provided are a method of adaptively allocating appropriate hybrid bursts according to terminal attributes including terminal position, channel state, and service type in an orthogonal frequency-division multiple access (OFDMA) system, and an upstream-MAP information element (US-MAP IE) structure supporting the method. The method includes dividing an upstream subframe into a plurality of zones depending on the number of OFDMA symbols and allocating bursts of a zone to a terminal according to the terminal attributes. Bursts are formed by allocating slots along a time axis in the upstream subframe, and are formed by allocating slots along a frequency axis in a downstream subframe.

Abstract: Provided are methods of spectrum sensing and assigning quiet periods in a cognitive radio system in order to increase the reliability of detection regarding whether an incumbent user appears in his/her frequency channel, customer premises equipment (CPE), a base station, and the structure of a super frame for performing the methods.

Abstract: A resource reservation method between a master device and a slave device or between slave devices in a centralized network. In resource reservation between slave devices, optimal resources may be allocated by performing link measurement between the slave devices before allocating the resources.

Abstract: Provided is a shaped-beam antenna having a multi-layered conductive element array surrounded by a dielectric ring. The shaped-beam antenna includes: a planar excitation element having a radiation structure according to a required polarization; a multi-layered conductive element array disposed on the planer excitation element, wherein the multi-layered conductive element array is formed by layering conductive elements at an arbitrary interval; and a dielectric ring surrounding the multi-layered conductive element array at a predetermined separation distance therefrom. Accordingly, it is possible to reduce the entire size of the shaped-beam antenna and manufacturing costs thereof.

Abstract: A method and apparatus for detecting a signal using a cyclo-stationary characteristic value is provided. A method of detecting a signal using a cyclo-stationary characteristic value includes: calculating cyclo-stationary characteristic values with respect to a cyclic frequency domain of an input signal; multiplying the calculated cyclo-stationary characteristic values with each other; and detecting the signal from the input signal based on the result of the multiplication.

Abstract: Provided is a loop antenna. The loop antenna includes a first antenna element embodied as a coaxial cable, a second antenna element embodied as a line and connected to one end of the first antenna element in series, a third antenna eLement embodied as a line, having one end connected to a ground plane and the other end connected to the other end of the first antenna element in series, and a power feeding cable for supplying power to the second antenna element.

Abstract: A channel switching method is provided for a base station to allocate a slot for data exchange with each of a plurality of terminals in a frequency channel that is not used by an incumbent user (IU). The method includes include transmitting a channel switching message for requesting to switch to a backup channel when a signal of the IU is sensed in the frequency channel; transmitting a beacon frame via the backup channel, wherein the beacon frame comprises allocation information about slots which are in the frequency channel and which are respectively allocated to each of the plurality of terminals; and allocating the slot for data exchange with each of the plurality of terminals to the backup channel according to the allocation information, and communicating with each of the plurality of terminals.

Abstract: The present invention relates to relay customer premises equipment (RCPE) for exchanging operational information and coexistence information of each cell between adjacent cells in a cellular system. The present invention enables effective control between multiple cells by directly transmitting operational information and coexistence information between cells over air links.

Abstract: An image reconstruction apparatus includes: a transmission signal generation unit configured to generate a transmission signal in an image reconstruction region, in order to acquire an image reconstruction value; an electromagnetic wave measurement unit configured to measure electromagnetic waves by receiving the transmission signal; an image reconstruction unit configured to update a parameter by using a matrix of matched system of a Sinc-Gauss-shaped basis function which is allocated to each node of a reconstruction mesh in the image reconstruction region, and generate an image reconstruction value; and an optimization determination unit configured to determine whether the parameter of the image reconstruction unit is optimized or not, and output the image reconstruction value or cause the image reconstruction unit to repetitively perform the calculation, wherein the reconstruction mesh has a grid structure of which the size is larger than that of a forward mesh and equal to the image spatial resolution.

Abstract: A wireless communication system provides a method and device for transmitting a preamble. A transmitter generates a first preamble sequence used for frequency offset estimation and generates a second preamble sequence according to the transmission mode. The transmitter transmits the first and second preamble sequences. With respect to the second preamble sequence, the phase thereof may be shifted into different phase offsets according to the transmission mode.

Abstract: Provided are a network communication method and a network device using a preamble. According to the network communication method and the network device, network coexistence is easily achieved by using network identification transmitted in the preamble, and an unknown terminal, which has a low reception signal to noise ratio (SNR) and has not yet been connected to an existing network, is easily connected to the existing network.

Abstract: Provided is a method for selecting an antenna performed by a receiver in a multi-antenna system. The method for selecting the antenna performed by the receiver in the multi-antenna system, comprises: a subcarrier group setting step for setting subcarrier groups by grouping subcarriers; a channel information acquisition step for acquiring channel information between a receiving end antenna and each of a plurality of transmission end antennas; an antenna selecting step for determining said subcarrier groups, which are to be transmitted to each of the plurality of said transmission end antennas on the basis of said channel information; and an antenna selection information transmission step for transmitting antenna selection information, which contains the result of said antenna selection, to a transmission end.

Abstract: Provided is an apparatus for controlling subcarrier spacing in a system supporting multiple frequency bands. The apparatus for controlling a subcarrier spacing comprises: an interference detection unit detecting interference over multiple frequency bands; a system parameter provision unit providing system parameters related to a subcarrier spacing between the multiple frequency bands—for example RF, FFT size, and channel bandwidth; a subcarrier spacing control unit controlling the subcarrier spacing such that the detected interference is reduced, on the basis of the system parameters. In a system operating with multiple bands, different subcarrier spacing can be applied by each band, thereby controlling interference occurring in each band.

Abstract: Provided are a method for using a flexible bandwidth in an orthogonal frequency division multiple access (OFDMA)-based cognitive radio system, and a base station (BS) and a subscriber station using the method. The method includes: allocating a channel band from among unused channel bands having a bandwidth that is a natural number times a bandwidth resolution to customer premises equipment (CPE), wherein the bandwidth resolution is a predetermined bandwidth smaller than a bandwidth of a broadcast channel band, and transmitting an OFDMA-based signal comprising band allocation information indicating information regarding the allocated channel band.

Abstract: A communication method of a transmitter using a preamble in a wireless communication system, includes determining at least two subcarriers from among a plurality of subcarriers, for the preamble; mapping a subcarrier sequence and a subcarrier phase value of the preamble to the at least two subcarriers; and transmitting the preamble using the at least two subcarriers. The preamble may include a real component having a first repeated pattern in a preset time interval, and an imaginary component having a second repeated pattern in the preset time interval, and a relationship between the first repeated pattern and the second repeated pattern may indicate characteristic information of the wireless communication system.

Abstract: The present invention relates to a system and method for managing resources, which involve managing a plurality of frequency resources in a communication system including a plurality of systems not having rights to use a first frequency band.

Abstract: An antenna radiation pattern measurement device that measures a radiation pattern of an AUT by using a source antenna includes a control unit, an analysis unit, and a measurement unit. The control unit controls driving of the source antenna and the AUT. The analysis unit measures an electric field value from a radio frequency (RF) signal that is transmitted from one of the source antenna and the AUT and received by the other antenna. In addition, the measurement unit controls the control unit and the analysis unit and measures a radiation pattern of the AUT by using the electric field value.

Abstract: The present invention relates to a method for reducing an average time period adopted at the time of evaluating an effect of electromagnetic fields of a mobile communication base station near the mobile communication base station on a human body and measurement is performed for 6 minutes at a predetermined measurement point for acquiring a whole body average by comparing a site measurement result targeting multiple base stations and uncertainty by repetitive measurement and when a 6-minute average value and an average value for a reduced time period which is shorter than 6 minutes are compared with each other, a standard deviation is equal to or lower than a predetermined level, e.g., 0.4 dB, it is sufficient even by the measurement for the reduced time period which is shorter than 6 minutes.

Abstract: A method and apparatus for modeling radio propagation is provided. In the method, when a wall having a thickness is modeled as a line having no thickness, an error in a shade area is minimized by considering the thickness of a wall while maintaining simplicity in a ray-tracing method.

Abstract: A probe and an antenna, more particularly, a probe and antenna using a waveguide, which reduces the multiple reflection of electromagnetic waves. The probe includes: and the antenna each include a waveguide and a resonance unit is entirely or partially disposed in the inside of the waveguide, and comprising the resonance unit including a conductor.